Not sewn or glued into the binding. An information sheet ‘laid in'--as in a publisher's slip or other information sheet.
Any form of paper loosely inserted in to the book, not glued.
A letter or other ephemeral items inserted but not glued into a book.
A letter, note or other piece of loose paper that is inserted into the book but not bound in or glued.
Paper/photograph/print is laid in (not glued down).
material such as a photo, letter, author-signed bookplate, or review slip that accompanies a book, but is not attached to it. see also Tipped In
(loosely inserted). Refers to a sheet of paper such as a letter or errata statement which is inserted but not glued into a book